An organic luminescence device is a device where a thin film including a fluorescent organic compound is sandwiched between an anode and a cathode, an electron and a hole are injected from the respective electrodes to generate an exciton of the fluorescent compound, and light which is emitted when the exciton returns to the ground state is utilized.
According to the study of Kodak company in 1987 (Appl. Phys. Lett. 51, 913 (1987)), there has been reported a luminescence with approximately 1000 cd/m2 at an applied voltage of approximately 10 V in a device having a separated-function type two-layer configuration using ITO as an anode, a magnesium-silver alloy as a cathode, an aluminum quinolinol complex as an electron-transporting material and a luminescent material, and a triphenyl amine derivative as a hole-transporting material. The related patents include U.S. Pat. No. 4,539,507 B, U.S. Pat. No. 4,720,432 B, U.S. Pat. No. 4,885,211 B, and so on.
In addition, it is possible to generate luminescence in the range of ultraviolet to infrared lights by changing the types of the fluorescent organic compound, and in recent years various types of compounds have been studied actively. For instance, it is described in U.S. Pat. No. 5,151,629 B, U.S. Pat. No. 5,409,783 B, and U.S. Pat. No. 5,382,477 B, JP 2-247278 A, JP 3-255190 A, JP 5-202356 A, JP 9-202878 A, JP 9-227576 A, and so on.
Furthermore, in addition to the organic luminescence device using the low molecular weight material as mentioned above, an organic luminescence device using a conjugate polymer has been reported by a group of the Cambridge University (Nature, 347, 539 (1990)). In this report, luminescence from a single layer is confirmed by the film formation of polyphenylene vinylene (PPV) using a coating system. The related patents of the organic luminescence device using the conjugate polymer include U.S. Pat. No. 5,247,190 B, U.S. Pat. No. 5,514,878 B, U.S. Pat. No. 5,672,678 B, JP 4-145192 A, JP 5-247460 A, and so on.
In this way, the recent progress in the organic luminescence device is remarkable, and the characteristics thereof suggest the possibility of applications for various purposes, which enable the luminescence device with a high luminance, a variety of luminescence wavelengths, a high-speed response, and a thin and lightweight form.
However, many problems still remain to be solved regarding the durability with respect to a change with time due to a long-term usage, deterioration caused by an atmospheric gas including oxygen, moisture, or the like, and so on. Besides, in the case of considering the applications to a full color display and so on, under the present conditions, there are needs for an optical output of higher luminance or higher conversion efficiency, and for luminescences of blue, green, and red having good color purity.
For instance, JP 2001-52868 A discloses a diamine compound but no blue luminescence with a high color purity (chromaticity coordinates: x, y=0.14 to 0.15, 0.09 to 0.10) has been obtained. In addition, an example of using a compound having a similar diamine skeleton is disclosed in JP 11-312587 A. However, there has been obtained no blue luminescence with a high color purity.